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121.
Patricia Göbel Julia Zimmermann Christoph Klinger Holger Stubbe Wilhelm G. Coldewey 《Journal of Soils and Sediments》2008,8(4):231-238
Background, aim, and scope The decentralised near-natural infiltration of storm water in urban areas over a long-term period can cause local pollution
of soil, seepage water and groundwater due to heavy metals (e.g. Pb, Zn, Cu), polycyclic aromatic hydrocarbons (PAH), petroleum
hydrocarbons and readily soluble salts, which compounds are partly classified as hazardous. The aim of this paper is to present
a recommendation matrix for suitable storm water infiltration devices. The scope is limited to eight different run-off types
and two different infiltration devices (swales and trenches with three different trench-filling materials) under two different
hydrogeological conditions (high adsorbing soil with low permeability, low adsorbing soil with high permeability). The examined
run-off types are sub-divided as follows: run-off from unpaved areas (gardens, grassed areas, cultivated land); green roofs,
aluminium roofs; roofs without zinc gutters and down-pipes; roofs with zinc gutters and down-pipes; copper roofs; zinc roofs
and trafficked areas (cycle and pedestrian ways, yards, car parks and residential roads). The recommendation matrix should
assist decision-makers such as city planners, architects and private house builders.
Materials and methods The potential for storm water infiltration to pollute soil, seepage water and groundwater is investigated with long-term 3-D
numerical water flow and chemical transport modelling in unsaturated and saturated zones over 50 years, which were already
presented by Zimmermann et al. (Water Sci Technol 51(2):11–19, 2005). The recommendation is based on a comparison between modelling results and several guideline values prepared by several
German authorities. The evaluation process leads to four hazard levels regarding the impact on topsoil (i.e. first 20 cm of
the soil), on seepage water (1 m below the infiltration device) and on groundwater (at the unsaturated–saturated boundary).
Results The recommendation matrix consists of 56 individual statements. Relating to dissolved organic substances like phenanthrene
and fluoranthene, the infiltration of trafficked areas run-off is critical. The infiltration of metalliferous run-off has
a high hazard accumulation potential. Here the storm water infiltration via sub-ground of low permeability and high adsorbing
soil material is critical for seepage water in any case; the infiltration of zinc roofs run-off via trench infiltration devices
is even critical for groundwater at 4 m depth. Sub-ground of low permeability and high adsorbing soil material has a lower
potential hazard in terms of storm water infiltration from roof run-off. The storm water infiltration via swales effects a
very large accumulation of heavy metals in the topsoil. The storm water infiltration via trenches leads to the accumulation
of hazardous substances in the deeper sub-ground, particularly where the trench-filling material has low adsorbing capacity
and high permeability.
Discussion The transferability of the results to other sites depends particularly on the hydrogeological conditions. Before using the
recommendation matrix, details of the hydrogeological conditions should be collected. The long-term simulation process is
simplified by several impact factors such as non-constant rainfall, soils heterogeneity, macro-porous flow, particle-bounded
transport and microbiological decomposition.
Conclusions Based on the scale of risks to soils, seepage water and groundwater, the matrix should be used in the selection of the roof
construction materials and appropriate storm water infiltration devices so that the environmental risks can be minimised.
If the sub-ground has a high permeability and low adsorption capacities, the infiltration of metalliferous roof run-off water
is, in general, not advisable without putting treatment facilities in place upstream. Thus, architects need to realise that
the choice of a suitable infiltration device depends, on the one hand, on the type of run-off and, on the other hand, on the
hydrogeological condition and the building materials.
Recommendations and perspectives Replacement of the topsoil in swale infiltration devices is recommended because, in particular, heavy metal (zinc) in run-off
from roofs with zinc gutters and down-pipes accumulates in the soil matrix. The replacement interval depends on the hydrogeological
conditions and, for this run-off example, lies between 10 and 20 years. If infiltration is essential, constructing special
treatment facilities upstream can be an alternative. The existing numerical model could be adapted to suit other site-specific
materials and be enhanced regarding several complex impact factors. 相似文献
122.
Claudia Kammann Christoph Müller Ludger Grünhage Hans-Jürgen Jger 《Soil biology & biochemistry》2008,40(9):2194-2205
To evaluate climate forcing under increasing atmospheric CO2 concentrations, feedback effects on greenhouse gases such as nitrous oxide (N2O) with a high global warming potential should be taken into account. This requires long-term N2O flux measurements because responses to elevated CO2 may vary throughout annual courses. Here, we present an almost 9 year long continuous N2O flux data set from a free air carbon dioxide enrichment (FACE) study on an old, N-limited temperate grassland. Prior to the FACE start, N2O emissions were not different between plots that were later under ambient (A) and elevated (E) CO2 treatments, respectively. However, over the entire experimental period (May 1998–December 2006), N2O emissions more than doubled under elevated CO2 (0.90 vs. 2.07 kg N2O-N ha−1 y−1 under A and E, respectively). The strongest stimulation occurred during vegetative growth periods in the summer when soil mineral N concentrations were low. This was surprising because based on literature we had expected the highest stimulation of N2O emissions due to elevated CO2 when mineral N concentrations were above background values (e.g. shortly after N application in spring). N2O emissions under elevated CO2 were moderately stimulated during late autumn–winter, including freeze–thaw cycles which occurred in the 8th winter of the experiment. Averaged over the entire experiment, the additional N2O emissions caused by elevated CO2 equaled 4738 kg CO2-equivalents ha−1, corresponding to more than half a ton (546 kg) of CO2 ha−1 which has to be sequestered annually to balance the CO2-induced N2O emissions. Without a concomitant increase in C sequestration under rising atmospheric CO2 concentrations, temperate grasslands may be converted into greenhouse gas sources by a positive feedback on N2O emissions. Our results underline the need to include continuous N2O flux measurements in ecosystem-scale CO2 enrichment experiments. 相似文献
123.
In agricultural headlands, rooting and yield of crops may be limited because of soil‐structure changes as a consequence of multiple passes of turning machinery. We hypothesized that perennial forage crops can substantially alter soil structure in agricultural headlands. On one experimental field and two commercial farms on Haplic Luvisols from respectively loess and sandy loess in the Lower Rhine Bay (Germany), we investigated how 4 y of continuously grown grass/clover or alfalfa affected soil structure and the performance of subsequent spring wheat. Compared with a crop rotation with annual plowing to 30 cm soil depth, perennial forage crops led to increased soil C content (+1.3% to +22.8%) and N content (+4.2% to +15.1%), higher densities of medium and coarse biopores at a depth of 35 cm, more large water‐stable soil macroaggregates, higher biomass and abundance of anecic earthworms, and higher grain yield and grain protein content of spring wheat grown as the following crop. Root‐length density of spring wheat in the subsoil was not affected by the preceding perennial fodder crops in two of the three field trials. We concluded that besides increasing N input to the soil, perennial cropping of grass/clover or alfalfa has effects on soil structure that may substantially reduce yield losses in agricultural headlands. 相似文献
124.
Karsten Wesche Benjamin Krause Heike Culmsee Christoph Leuschner 《Biological conservation》2012,150(1):76-85
There is growing concern that biodiversity loss in European agricultural landscapes is having negative effects on functional trait diversity. Long-term studies examining vegetation changes from the period before agricultural industrialisation are however rare. Here, we ask how management intensification and increased nutrient input initiated in the 1950/1960s have altered grassland plant community composition, species diversity and functional trait composition using comprehensive datasets from five floodplain regions (plus one protected reference region) in northern Germany. Sites with available historical relevés and vegetation maps (1950/1960s, 1990s) were resampled in 2008 to facilitate the analysis of a period spanning four to five decades.Plant community composition changed tremendously in all study regions during the 50 year period, which was related to increasing Ellenberg indicator values for nutrient availability. Species richness at the plot-level fell by 30–50% over the period, and losses in functional diversity were equally large. A non-formal comparison with the results from the protected reference study region indicates that the changes may mostly be attributable to local nutrient input rather than to supra-regional climate change. Our results indicate a consistent trend towards much more species-poor communities dominated by mow-tolerant, N-demanding competitive grasses, whereas species with more ruderal strategies, species flowering early in the season and, in particular, insect-pollinated herbs have all decreased. The substantial loss of nectar-producing grassland herbs is likely to have negative effects on the abundance of pollinating insects, with consequences for the grassland animal communities. This highlights the growing need for adequate grassland management schemes with low N input to preserve high-nature-value grassland. 相似文献
125.
Cornelia Lehmann Christoph Biela Stefan Töpfl Gisela Jansen Rudolf Vögel 《Euphytica》2007,158(1-2):189-199
The objective of this study was to examine the potential of Solanum scabrum to provide a colorant for food. We conducted a field trial with eight accessions from four different sources and recorded
both morphological variability and fruit yield differences between accessions. Further, anthocyanin and glucoalkaloid concentrations
were determined. The accessions could be assigned to two distinct groups: a leafy vegetable type with toxic fruits used in
Africa and a berry type with edible fruits known as Garden Huckleberry in North America, but both types had edible leaves
with low glucoalkaloid concentrations. The leafy vegetable type set not much fruit. In contrast, the berry type yielded on
average 800–900 g berries per plant with remarkable high anthocyanin concentrations of 8.1–13.9 g kg−1 fresh weight, calculated as petunidin 3-p-(coumaryl-runtinoside)-5-glucoside. Thus, S. scabrum can serve as a source for natural anthocyanin pigments. In particular, two accessions with a high fruit yield were promising
candidates as a berry crop. One had the best anthocyanin concentration of the examined material and the other one had a low
percentage of unripe berries as a further advantage. 相似文献
126.
Structural basis of Wnt recognition by Frizzled 总被引:1,自引:0,他引:1
Wnts are lipid-modified morphogens that play critical roles in development principally through engagement of Frizzled receptors. The 3.25 angstrom structure of Xenopus Wnt8 (XWnt8) in complex with mouse Frizzled-8 (Fz8) cysteine-rich domain (CRD) reveals an unusual two-domain Wnt structure, not obviously related to known protein folds, resembling a "hand" with "thumb" and "index" fingers extended to grasp the Fz8-CRD at two distinct binding sites. One site is dominated by a palmitoleic acid lipid group projecting from serine 187 at the tip of Wnt's thumb into a deep groove in the Fz8-CRD. In the second binding site, the conserved tip of Wnt's "index finger" forms hydrophobic amino acid contacts with a depression on the opposite side of the Fz8-CRD. The conservation of amino acids in both interfaces appears to facilitate ligand-receptor cross-reactivity, which has important implications for understanding Wnt's functional pleiotropy and for developing Wnt-based drugs for cancer and regenerative medicine. 相似文献
127.
Roos CF Riebe M Häffner H Hänsel W Benhelm J Lancaster GP Becher C Schmidt-Kaler F Blatt R 《Science (New York, N.Y.)》2004,304(5676):1478-1480
We report the deterministic creation of maximally entangled three-qubit states-specifically the Greenberger-Horne-Zeilinger (GHZ) state and the W state-with a trapped-ion quantum computer. We read out one of the qubits selectively and show how GHZ and W states are affected by this local measurement. Additionally, we demonstrate conditional operations controlled by the results from reading out one qubit. Tripartite entanglement is deterministically transformed into bipartite entanglement by local operations only. These operations are the measurement of one qubit of a GHZ state in a rotated basis and, conditioned on this measurement result, the application of single-qubit rotations. 相似文献
128.
Hall N Karras M Raine JD Carlton JM Kooij TW Berriman M Florens L Janssen CS Pain A Christophides GK James K Rutherford K Harris B Harris D Churcher C Quail MA Ormond D Doggett J Trueman HE Mendoza J Bidwell SL Rajandream MA Carucci DJ Yates JR Kafatos FC Janse CJ Barrell B Turner CM Waters AP Sinden RE 《Science (New York, N.Y.)》2005,307(5706):82-86
129.
West NP Sansonetti P Mounier J Exley RM Parsot C Guadagnini S Prévost MC Prochnicka-Chalufour A Delepierre M Tanguy M Tang CM 《Science (New York, N.Y.)》2005,307(5713):1313-1317
Shigella, the leading cause of bacillary dysentery, uses a type III secretion system (TTSS) to inject proteins into human cells, leading to bacterial invasion and a vigorous inflammatory response. The bacterium is protected against the response by the O antigen of lipopolysaccharide (LPS) on its surface. We show that bacteriophage-encoded glucosylation of Shigella O antigen, the basis of different serotypes, shortens the LPS molecule by around half. This enhances TTSS function without compromising the protective properties of the LPS. Thus, LPS glucosylation promotes bacterial invasion and evasion of innate immunity, which may have contributed to the emergence of serotype diversity in Shigella. 相似文献
130.
Herbert A Gerry NP McQueen MB Heid IM Pfeufer A Illig T Wichmann HE Meitinger T Hunter D Hu FB Colditz G Hinney A Hebebrand J Koberwitz K Zhu X Cooper R Ardlie K Lyon H Hirschhorn JN Laird NM Lenburg ME Lange C Christman MF 《Science (New York, N.Y.)》2006,312(5771):279-283
Obesity is a heritable trait and a risk factor for many common diseases such as type 2 diabetes, heart disease, and hypertension. We used a dense whole-genome scan of DNA samples from the Framingham Heart Study participants to identify a common genetic variant near the INSIG2 gene associated with obesity. We have replicated the finding in four separate samples composed of individuals of Western European ancestry, African Americans, and children. The obesity-predisposing genotype is present in 10% of individuals. Our study suggests that common genetic polymorphisms are important determinants of obesity. 相似文献